Lectures

1. III. A Closer Look at Natural Selection
A. Natural selection, adaptation, and evolution
B. Patterns of natural selection
1. Directional selection
2. Stabilizing selection
3. Diversifying selection
C. Effects of selection on the distribution of phenotypes

2. aa AA
aa
aa
Positive assortative
mating
Negative assortative
mating
X X
All offspring
homozygous
All offspring
heterozygous
Non-random mating affects the frequency of genotypes in a
population, but does not change allele frequency

3. Biston betularia - the peppered moth
Grey moth on lichen
Dark morph on sooty tree
Each morph on the “wrong” tree

4. Industrial Melanism in the peppered moth
Released in rural woodland
grey melanic
# released 496 473
# recaptured 62 30
% recaptured 12.5 6.3
Released in industrial region
grey melanic
# released 137 447
# recaptured 18 123
% recaptured 13.1 27.5

5. Fig. 23. 12